A test for comparing the means of two samples, or the mean of one sample (or even parameter estimates) with a specified value; also known as the "Student t-test" after the pseudonym of its inventor.

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Longitudinal data where individual id is not available

I am associated with a teaching hospital, and medical students are frequently administered tests and measures to monitor their progress. I am not talking about exam results here, but of psychological ...
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2answers
16 views

Comparing the mean difference between data measured by different equipment, t-test suitable?

My problem is as follows: I have 2 measuring devices, both using different measuring techniques, each trying to quantify properties of objects passing their measurement area. The devices measure the ...
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1answer
21 views

Inconsistent x-y relationship from paired t-test and linear regression

I am analyzing an experiment comparing the effect of treatment A vs. B on the matched subject. Here are the measurements on 34 subjects: ...
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2answers
39 views

Should I perform multiple t-test or an ANOVA?

My causal comparative study seeks to three questions related to the hypothesis: a) is there a statistically significant difference between the academic achievement of 6th grade mathematics students ...
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4answers
32 views

Two groups are significantly different? Test to use

I have two groups of discrete data (integers): ...
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21 views

T-Tests and Regressions

my supervisor has asked me a few questions that I'm not entirely sure how to answer. For a quick summary, my study includes a small sample of 16. To describe the sample, I compared the scores of the ...
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18 views

Estimating the absolute decline of rates

Giving it another shot at describing my problem properly. I want to calculate the the crude event rates (10000person/years) for patients heart failure debut (variable name "heart_estimate") during ...
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25 views

ttest for specified variables [duplicate]

Im fairly new to SAS and have a problem with paired ttest. I have 2 variables and 5 unique observations for each. Variables are "Year" and "heart_estimate" "Year" "heart_estimate" 01 20 ...
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17 views

Two sample differences between percentage means with negative percentages

Hello to everyone and thank you for all the help you've already unknowingly provided to me in the past. I have a group of percentages around zero that are grouped into two categories, and I wanted to ...
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1answer
20 views

Equivalent of paired $t$-test for dispersion

I'd like to compare, in a within subject design, the dispersion of two conditions. At first I thought about taking the standard deviation by individual and condition, and compute a paired $t$-test on ...
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61 views

Analysis for cross-subjects correlation

Suppose that an investigator has collected some longitudinal data from each of the $n$ subjects, and that a correlation coefficient is computed on the data between any pair of subjects, leading to ...
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1answer
24 views

Confidence Interval and Signifcance test Question

I have done the first part of the question already I just need help on the second part. You read in a U.S Census Bureau that a 99% confidence interval for the mean income in 2005 of American ...
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27 views

Determining which t-test is right?

I have already solved this question, but I need some feedback. A new method for measuring blood pressure in laboratory mice using radiotelemetry has been proposed. How does this compare with the ...
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0answers
15 views

Test mean for discrete data [closed]

This is a hypothetical case. I would like to conduct a survey on how many times people visited the cinema in the previous month. I would like to confirm whether the mean value I obtained from my ...
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2answers
70 views

Can I do a t-test Power Analysis for Unequal Size Groups which Produces 2 Different Minimum n's?

It's usually straightforward to do a Power Analysis to compute the minimum sample size, especially in R which is my preferred ...
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37 views

Where can I find unit tests for evaluating my student t-test?

I have written a paired t-test and I am looking for some standard unit tests that I can make sure my code is correct. Do such tests exist? How does R take care of unit testing for its t.test()?
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0answers
33 views

What is a correct way to test these data for significance?

I have data on 1548 disease cases and 1137 controls. Specifically, for each person, I have a certain score $n$. I am interested in the following: First, for either group, I want to know if the ...
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21 views

Calculating Hedge's g and its variance from t-statistic

I believe there is a way to calculate Hedge's g and its variance from a t-statistic. I have found the formulas to calculate Hedge's g from one-sample t, and from independent groups t. one sample: ...
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34 views

appropriate hypothesis test for non-negative quantity

This question is intentionally written in a very abstract way, because I am interested in a generic solution, or for pointers to different possible concrete cases in different fields: I am measuring ...
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1answer
13 views

Comparing means between groups where not all samples are independent

How does one compare means between two groups that contain repeated measures. For instance: Group 1 = has mutation A Group 2 = has mutation B Dependent variable = blood pressure (continuous ...
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20 views

Statistical test on pairs of percentages

I am quantifying a measure of correlation in a graph/network under two different experimental conditions to determine whether there is a significant difference in the measure given by the change of ...
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0answers
18 views

Paired t-test for data sets obtained by best fits

I have a bunch of features that I'm trying to measure before and after applying a certain process. I want to see if the process I'm applying is changing the relative orientation of the features among ...
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1answer
93 views

Relationship between paired t test and simple mixed model

The bounty I placed on this question expires in the next 24 hours. I have a psychological data set which, traditionally, would be analysed using a paired samples t test. The design of the ...
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3answers
71 views

Large sample size for t-test

I am working on a physics experiment, and I ran 500 runs to calculate a parameter. I want to use the t-test to see if my mean from 500 runs matches the actual value. u0: mean is actual value u1: ...
2
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2answers
103 views

Is a one sample t test the right approach for this question?

This is an example from my book that I'm trying to figure out but I'm totally lost. Can someone complete this step by step so I understand? A new meditation technique based on making barnyard ...
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1answer
30 views

Power calculation; determine required difference in means

I want to perform a power analysis for a 2 sample t-test for the difference in means. However, instead of computing the required sample size, I would like to compute the required difference in the ...
2
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1answer
38 views

Comparing Multivariate Means

Apologies in advance if this is very basic; I am quite new to statistics. I have a large set of 7 dimensional data, for two groups. In my example, they are express relative preferences over a ...
3
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1answer
47 views

Studentized residual distribution

I read that in a regression with $k$ regressors, the t-statistic corresponding to a certain coefficient follows a $t(n-k)$ distribution. However, later on I read that studentized residuals follow a ...
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3answers
57 views

Test if advertising raised sales?

I have an (offline) advertising campaign that I'm running in one city. I'm trying to figure out how to answer the following questions: What are the chances that the advertising campaign has no ...
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1answer
40 views

How do I test differences in reaction times?

I have data from an experiment in which participants had to respond to stimuli in two different conditions in a within-subject design. Obviously, I can fairly easily test for differences in accuracy ...
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1answer
27 views

Bayesian alternative or complement to the Student t-test

I was just recently using the Student t-Test to check whether values from two samples could have an identical mean or not. I was wondering whether there is a complementary technique in bayesian ...
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26 views

Sample size calculation for paired t-test single arm using r

I am planning a study on alteration in AUC of a drug due to a surgery of gastrointestinal tract. It's a pre-post study. A group of patients will undergo blood sampling for AUC (area under curve) both ...
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4answers
129 views

Simple Question regarding t-tests

I have the mean from a previous study (the Brief Symptom Inventory) that I would like to compare the mean found in my study. Both samples have a population over 100. I do not have the entire data set ...
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14 views

Is Monte Carlo simulation more appropriate than parametric tests for constructing confidence intervals for weighted means?

A colleague suggested that Monte Carlo simulation should be preferred for constructing confidence intervals for weighted means calculated from a sample. How and why exactly might Monte Carlo perform ...
0
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1answer
10 views

T-test on indicator for a group of betas vs. F-test on the same group

If I estimate the following regression on a large data set: $y = b_0x_0 + b_1x_1 + b_2x_2 + b_3x_3 + b_4x_4$ where $x_0, x_1,...x_4$ are all dummy variables indicating group membership, and I create ...
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1answer
24 views

Show “Does it affect?” with hypothesis test

I am trying to learn ttest and ANOVA for my project (i am a computer science student). I need to know that my subjects answers "effected" by the feedback they get from the first question. What should ...
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2answers
28 views

Shouldn't a weighted t-test and a weighted linear regression yield the same standard error on the estimated mean?

I have a vector of values and a vector of the reciprocal of their standard error. I'd like to estimate their mean and the standard error on the mean. At first I used linear regression using the ...
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2answers
51 views

Analyzing Difference in Change between two groups with unpaired samples

I'm currently working with a data set where there is a control group and an intervention group. There are a couple of data points where we're interested in seeing if the intervention group has a ...
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1answer
26 views

How to do significance testing on averages of regression coefficients across multiple groups?

I have over 1000 respondents each with their own regression coefficients. I am analyzing data by different segments by averaging the constant and coefficient scores for each group. Sometimes I will ...
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1answer
34 views

How to compare means of repeated measures between groups in SPSS

I'm having trouble regarding which test to run on my data in SPSS. I have two groups (condition1 and condition2) which is also my independent variable (categorical). Both groups were asked to rate ...
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15 views

How do I compare means of the same group on two continous variables?

I would like to compare the means of the same group on two continuous scales. I want to see if the scores are significantly different on the scales. Which statistical test do I use for this?
3
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1answer
40 views

Loss function that relates ROPE with HDI?

In Doing Bayesian Data Analysis (link to the book) and Bayesian Estimation Supersedes the t-Test, J. Kruschke proposes using the following criterion to reject or accept the null hypothesis in a ...
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1answer
40 views

statistics t test sample size

in the formula for t test, t = (mean1 - mean2)/sqrt[(var1 + var2)/N] is N the total number of subjects in both groups being compared or the number of subjects in each group or condition? df = N-2 ...
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1answer
33 views

Designing Frequentist A/B Experiments

What parameters should one pre-specify before running an experiment? (e.g. a two-sample, one-side, t-test) My understanding is that on establishes: Null hypothesis Maximum Significance level ...
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27 views

Estimating Sample sizes for Null Hypothesis Testing

Wikipedia has the following table for computing sample sizes:                                       ...
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1answer
46 views

Calculate p-value for main effect in 2x2 design

How can I obtain a p-value for a main effect in a 2x2 design? I have 12 participants and 2 independent condition categories which I represent by letter, and case. That means my conditions are A, a, ...
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25 views

Choosing correct statistic aproach for dropout analysis

I need some input from you. At the moment, I feel a gap opening between theoretical knowledge and practical implementation. Problem case: In my study, I did an identic training program, around 10 ...
2
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1answer
26 views

How to define Confidence Intervals from a distribution of 1000 t-statistics?

I have a vector of length 300 containing some kind of values (say, scores of a math test). The distribution is not normal. I want to test if the average score of a small group (30 samples) is ...
3
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2answers
47 views

Can you compare two groups with only partial summary information?

I have to group $A$ ($\bar X_1 =20, N_1=10$) and group $B$ ($\bar X_2 = 25, N_2=15$). Is there a way I can compare these two groups and get some statistical significance? I was thinking about using ...
2
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0answers
31 views

Why use the student's t-distribution rather than the student's z-distribution

So suppose I'm trying to decide whether to reject the null-hypothesis that the mean of some random variable $X$ is zero based on the sample mean $\hat{\mu}$ computed from n IID draws of this random ...